Use proper "codec → stream codec" method, do away with unwise cast

Could help address #196

Author: 62832

src/main/java/gripe/_90/megacells/misc/CompressionChain.java

@@ -189,10 +189,12 @@ public int hashCode() {
     }
 
     record Variant(AEItemKey item, int factor) {
-        private static final StreamCodec<RegistryFriendlyByteBuf, AEItemKey> ITEM_KEY_CODEC =
-                AEItemKey.STREAM_CODEC.map(k -> (AEItemKey) k, k -> k);
         private static final StreamCodec<RegistryFriendlyByteBuf, Variant> STREAM_CODEC = StreamCodec.composite(
-                ITEM_KEY_CODEC, Variant::item, ByteBufCodecs.VAR_INT, Variant::factor, Variant::new);
+                ByteBufCodecs.fromCodec(AEItemKey.CODEC),
+                Variant::item,
+                ByteBufCodecs.VAR_INT,
+                Variant::factor,
+                Variant::new);
 
         private BigInteger big() {
             return BigInteger.valueOf(factor);